The present invention relates to illumination devices for use in surgery on the human body and more particularly to such devices especially suited for use in ophthalmic surgery and the like.
It is known that ophthalmic surgery (and other types of surgery such as laparoscopic and orthroscopic surgery) as well as various procedures such as endoscopy typically require an illumination probe or device which provides illumination for the area under treatment. To provide the best possible visualization for the physician/user of the device, it is preferred that the output of the illumination device be broadband (simulating sunlight to some degree), that the device itself be rather small (so as to not interfere with other instruments being used in the procedure, for example), that the device illuminate a relatively large area at one time, and that the light output over the illuminated area be fairly uniform (eliminating dark spots, excessively bright spots, etc.).
Often the illumination is transmitted from an illumination source (disposed at some distance from the patient) through an optical fiber cable to a handpiece which is manipulated by the physician/user or an assistant to provide illuminating light on the desired area.
Optical fiber cables do a good job of providing broad spectrum light from a suitable illumination source, but the light output of optical fibers could be improved. For example, the numerical aperture of optical fibers are typically rather small, with the result that the field of illumination for these devices is smaller than could be desired. Moreover, these devices are most often used in liquids (saline solutions and the like) which further reduces the field of illumination. Lenses have been used to spread the light from optical fibers, but these heretofore have resulted in uneven illumination (dark spots, bright spots, light rings, dark rings, etc.). At least one device (manufactured by Trek Medical) has been proposed to spread the light by changing the distal configuration of the optical fiber itself from the standard blunt shape. This Trek Medical device is believed to have included a cone formed into the distal end of the optical fiber with the tip of the cone forming the distal end of the fiber. This device also resulted in uneven light distribution.